Worsening of anemia increases the risks of complications and prolonged length of stay following revision total shoulder arthroplasty.

Background: There are no studies currently in the literature that assesses complications following revision total shoulder arthroplasty (TSA) in patients with varying severity of anemia. The purpose of this study was to determine the impact of preoperative anemia severity on postoperative complications following revision TSA. Methods: Patients undergoing revision TSA from 2013 to 2019 were queried in a national database. Based on previous studies' definitions of anemia, three subgroups were stratified: patients without anemia (hematocrit >36% for women, hematocrit >39% for men), patients with mild anemia (hematocrit 33% to 36% for women, hematocrit 33% to 39% for men) and patients with moderate to severe anemia (hematocrit <33% for both women and men). In this analysis, patient demographics, comorbidities, and postoperative complications were compared between the three groups. Results: Of 1559 total patients undergoing revision TSA, 1178 patients (75.6%) did not have anemia, 255 (16.3%) had mild anemia, and 126 (8.1%) had moderate/severe anemia. Following adjustment on multivariate analysis, patients with mild anemia were more likely to have postoperative transfusion and extended length of stay compared to non-anemic patients. Patients with moderate/severe anemia were at increased risk of postoperative transfusion, sepsis, extended length of stay, and reoperation compared to non-anemic patients. Discussion: From mild anemia to moderate/severe anemia, there was a stepwise increase in the risk of postoperative complications. Our study showed that there is clinical value in the preoperative correction of anemia for these patients as it relates to complications and hospital stay. Level of Evidence: III.